peters



. 2 Sheets-*Sheet 1.

(No Model.) s

` A. C.4 RAND.

Valve Gear.

N. PETERS. FHOTOLIT (No VModel.) 2 sheets-sheet 2.

AQe. RAND. Valve Gear. No. 230,336. Patented July 20,1880.

lll I l vIl y NIH l l l IIIII I l Wifneses;

N.FEI'ERS. PHOTDALITHUGHAFMER. WASHINGTON, D4 CA KUNITED STATES PATENT OFFICE.

ADDISON O. RAND, OF NEW YORK, N. Y.

VALVE-GEAR.

SPECIFICATION forming part of Letters' Patent No. 230,336, dated July 20, 1880. l

Application filed April 2, '1880. (No model.)

To all whom it may concern:

Be it known that I, ADDISON O. RAND, of

vthe city and State of New York, have invented certain Improvements in Valve-Gears for Steam-Engines, Steam-Stamps, Steam-Drills, &c., of which the following is a specitication.

My improvements relate to that class of valve-gear in which the valve is operated by a motion derived from the piston.

It is the object of my improvements to adapt this class of valve-gear for employment in an. engine in which steam is used expansively; and the main feature of my invention consists in giving tothe piston the capacity of imparting to the steam-valve an intermittent motion in each direction, whereby each complete movement of the valve, whether oscillatory or reciprocatory, is ett'ected by two successive steps, the tirst step serving to impart sufficient range of motion to the steam-valve to enable it to close the previously-open steam-port and cut off the supply ot' steam, thus leaving the steain in one end of the cylinder to act eXpansively, and the second step serving to continue the throw ot' the steam-valve sutticientl y to enable it to open the other v steam-port and admit steam into the opposite end of the cylinder, steam being admitted into the appropriate port at the close of each stroke, and heilig cut oft' at any predetermined part of the stroke, the exhaust-valve, also operated by the piston, remaining open during each stroke until the instant before the final movement of the steamvalve admits steam into the cylinder.

The accompanying drawings represent my invention embodied in tha-t form ot valve-gear in which the valve is reciprocated by the action of a T lever or rocker, the free ends of which penetrate the cylinder and are oscillated by collisions alternately with the opposite inclined end walls of a recess in the periphery of' the piston.

In these drawings, Figure 1 is a central longitudinal section of the cylinder and valvechests, exhibiting the piston in elevation, showing the steam-passages and the steam and eX- haust valves and the T-levers by which the valves are respectively operated. Fig. 2 is a transverse section through the line x on Fig. l. Fig. 3 is a View otl the exhaust-valve seat. Fig. 4 is a transverse section through the line y y on Fig.`l. Figs. 5, 6, and 7 illustrate a modification in the arrangement of the valve-chests with relation to the cylinder, Fig. 5 being an elevation, Fig. 6 a transverse section through the line z z on Fig. 5, and Fig. 7

an end elevation thereof.

The drawings represent a steam-cylinder, A, provided on one side with an exhaust-valve chest, B, and upon the other side with a steamvalve chest, C.

Steam is admitted into the exhaust-valve chest through the steam-pipe D, and by its pressure holds the exhaust-valve E against its seat E. From the exhaust-valve chest steam is conducted through the steam-passage d into the chest O of the steam-valve F, by the operation ot' which steam is admitted alternately into the opposite ends ofthe cylinder through the inlet-passages f and j". The exhauststeam escapes through the passages c and e alternately, and through the exhaustvalve into the space surroumling the exhaust-valve lever E2, from which it is discharged through the exhaust-pipe E,the mouth ot' which is shown in dotted lines in Fig. 1. The steamvalve F is held upon its seat F by the pressure ot' the steam in the chest C, and is reciprocated bythe oscillation of the T-lever F2 upon its pivot F3.

The free ends E4 and E5 of the exhaust-valve lever E2, which oscillates upon the pivot E6, are alternately projected.- into the path ot' the piston, from which they are thrown by collisions, respectively, with the inclined en'd walls, G and G', of a recess formed in the periphery` ot' the piston H.

As represented in Fig. 1, the free end E5 ol" the T-lever E2 has just .been so thrown out otl the path ot' the piston by collision with theinclined end wall, G', ot' the recess, and in operation will remain in the position shown until the other free end, E4, is brought by the inward movement of the pistoninto collision with the opposite inclined end wall, G, ot' the recess, the parts being so proportioned that the collision of the free end E4 with the inclined end wall, G, will immediately precede the collision of the same end wall, Gr, with the free end F4 of the T-lever F2, which operates the steam-valve, the object of this order of operation being to close the mouth of the er;

haustpassage immediately before steam is admitted into the inlet-passage to effect the stroke in either direction.

In the position shown in Fig. 1 the free end F5 of the T-lever F2 is represented as bearing upon the periphery of thelargest portion H of the piston, having been thrown into that position by collision with the inclined end wall, G', while the free end F4 is represented as resting upon the bottoni of the deep central recess, I.

By theinward movement of the piston in the direction shown by the arrowi the free end F4 of the T-lever F2 will be brought into collision with the inclined end wall, J, of the deep recess Land, riding` over the inclined end wall, J, will be brought to a bearing upon the bottom of the shallower recess K. At the same time the free end F5 will be rocked inward until it bears upon the bottom of the opposite end portion. K', otl the shallower recess, thus holding theT-leverFstationary. There will thus be effected apositive movementof the inlet or steam valve of the precise range required to enable it to close the inletpassagef without opening,

the inlet-passagej".

5y the continued inward movement of the piston the free end F4 of the T-lever will be brought into collision with the inclined end wall, G, of the shallower recess, and, riding up over that, will bear upon the largest diameter, H, of the piston, and by the consequent further oscillation ofthe T-lever F2 the valve F will be thrown sufficiently far to open the inlet-passagej" and admit steam into the bottoni ofthe cylinder. In this position the free end F5 of the T-lever will rest upon the bottom ofthe deep recess, I, and by the return movement. of the piston willbe at first broughtinto collision 'with the inclined end wall, J', of the deeprecess,and subsequently with theinclined end wall, G', of the shallower recess, tirst closing the inlet-passage j", then, by its further movement, opening the inlet-passage j".

In the drawings the central portion of the piston is represented as being turned down to form annular recesses in its periphery, thus adaptingthe structure for cmploymentin rockdrills, in which the piston, in addition to its reciproca-ting` movement, is made to rotate intermittently upon its longitudinal axis.

It will oi' course be understood that in those cases where a rotary movement of the piston is not required a narrow longitudinal groove ina-y be formed in the periphery of the piston, having its central portionudeeper than its end portions, and that such a`groove,being provided with inclined end walls, will answer the saine purpose in operating the T-lever F2 as the annular recesses shown in the drawings.

rlhe part of the stroke at which steam is cnt otf depends upon the length of the deep central recess, I. rlhe shorter that recess the earlier in the stroke will the cutting oft' be effected, and in practice the length of the deeper recess I, and consequently the part of the' Iod outside the cylinder, for the purpose ol" workin g a valve provided with a stem or shaft projecting outside the valve-chest, this part of my invention being present in any engine, in which the steam-valve is given a two'step movement by mechanism actuated by the piston.

I claim as my invention in a steam-engine in which the inlet or steam valve is operated by the pistonl. The combination ofthe steam-valve Fand the T-lever F2 with a piston the periphery ot' which is recessed to variable depths, substan= tially as and for the purpose set forth.

2. rlhe T-lever F2, for operating the steamvalve F, provided with the free ends F4 and F5, in combination with the bearings l( and K, formed by the relatively shallower part of the recess l in theperiphery of the piston, whereby the valve is held stationary at the conclusion of the iirst step of its movement in either di-` rection, substantially as set forth.

3. The combinationot' the steam-valve F and its actuating mechanism with the exhaustvalve E and the T-lever E2, operated by a recess in the periphery of the piston, substantially as set forth.

4. The exhaust-valve E and the exhaustvalve chest B, in combination with the steampipe l) and the conductingpassage d, whereby the exhaust-valve is held upon its seat by the pressure of the live steam, substantially as described.

5. ln combination with a valve and suitable intervening mechanism, the piston H H, having formed in its peripheryrecesses of variable depths, substantially as and for the purpose Set forth.

ADDISON G. RAND.

itnesscs HENRY M. CoWLEs, GILBERT WEssELLs, Jr.

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